The purpose of this research is to continue to study architectonic and other neuroanatomical asymmetries in the brains of man and selected non-human species. Asymmetries will be studies in the inferior parietal lobule of man, a region relevant to language function and with known gross anatomical asymmetries; asymmetries will be studied in the auditory regions of Macaca fuscata, an animal with suggested ear lateralization for special sounds; asymmetries will be studied in Wistar rats already tested during life to show behavioral asymmetries in turning behavior; asymmetries and other architectonic characteristics will be specified in brains of patients with developmental dyslexia, and in selected brains of patients with well circumscribed syndromes of language dysfunction; and asymmetries and other architectonic characteristics will be specified on the brains and spinal cords of Sherman rats in which exposure to certain drugs before birth has resulted in the asymmetric malformation of a limb or limbs. The nervous tissues will be processed according to established histological procedures and analyzed architectonically and, in some cases, connectionally according to criteria well established in the literature and in our laboratory. The long-term objectives will be to enlarge our knowledge of normal cerebral asymmetries in human and other mammalian brains, to specify abnormalities in anatomical lateralization possibly responsible for clinical disorders of language function, and to attempt to develop animal models of brain asymmetry in which to study mechanism of laterizations.